Rotor core and superconducting rotating machine with the rotor core

Abstract

Provided are a rotor core, a method for cooling a rotor core, and a superconducting rotating machine, capable of effectively and uniformly cooling superconducting coils without causing cold brittleness in an extremely low temperature. The rotor core 10 , which is made of a substantially hollow cylindrical member of nonmagnetic material, has a cylindrical cavity 13 defined therein and extending in the longitudinal axis of the member. Helium gas 300 is delivered in the rotor core 10 from the proximal to distal sides and vice versa, which ensures a uniform cooling of the rotor core 10 . This also ensures a uniform and effective cooling of the superconducting coils.

What is claimed is: 
     
       1. A rotor core for use in a superconducting rotating machine, comprising:
 a substantially hollow cylindrical member made of non-magnetic material,
 the cylindrical member having:
 a longitudinal axis, 
 a cylindrical cavity defined therein and extending along the longitudinal axis, 
 a plurality of recesses defined on an outer peripheral surface of the cylindrical member for receiving superconducting coils, 
 a plurality of cryogen passages defined therein adjacent the cylindrical cavity and extending therethrough between a proximal side and a distal side thereof, the cryogen passages having at least two first passages for guiding the cryogen from the proximal side to the distal side and at least two second passages for guiding the cryogen from the distal side to the proximal side and the first and second passages being arranged alternately and spaced at regular intervals with respect to a peripheral direction about the longitudinal axis, 
 a first supply tube having a proximal end connected to proximal ends of the first passages; 
 a first return tube having a distal end connected to distal ends of the first passages, the first return tube being extended from the distal side to the proximal side through the cylindrical cavity; 
 a second supply tube extended from the proximal side to the distal side through the cylindrical cavity, the second supply tube having a distal end connected to distal ends of the second passages; and 
 a second return tube having a proximal end connected to proximal ends of the second passages. 
 
 
 
     
     
       2. The rotor core of  claim 1 , further comprising rod-like members each coaxially disposed in the cryogen passage to leave a space gap around the rod-like member. 
     
     
       3. The rotor core of  claim 2 , wherein either an inner surface of each of the cryogen passages or an outer surface of each of the rod-like members has convex or concave portions defined therein and extending in a peripheral direction thereof. 
     
     
       4. A superconducting rotating machine having a stator and a rotor, electromagnetically connected with each other, comprising a rotor core defined in  claim 1 . 
     
     
       5. A rotor core for use in a superconducting rotating machine, comprising:
 a substantially hollow cylindrical member made of non-magnetic material,
 the cylindrical member having:
 a longitudinal axis, 
 a cylindrical cavity defined therein and extending along the longitudinal axis, 
 a plurality of recesses defined on an outer peripheral surface of the cylindrical member for receiving superconducting coils, 
 a plurality of cryogen passages defined therein adjacent the cylindrical cavity and extending therethrough between a proximal side and a distal side thereof, the cryogen passages having at least two first passages for guiding the cryogen from the proximal side to the distal side and at least two second passages for guiding the cryogen from the distal side to the proximal side and the first and second passages being arranged alternately and spaced at regular intervals with respect to a peripheral direction about the longitudinal axis, 
 a first supply tube connected to proximal ends of the first passages; 
 a first return tube connected to distal ends of the first passages and extended from the distal side to the proximal side through the cylindrical cavity; 
 a second supply tube extended from the proximal side to the distal side through the cylindrical cavity and connected to distal ends of the second passages; and 
 a second return tube connected to proximal ends of the second passages.